Shingle-like slab forming process and apparatus



Sept. 26, 1933. ow LL SHINGLE LIKE SLAB FORMING PROCESS AND APPARATUS Filed Nov. 28, 1930 Hill 1 H IIT ' INVENTOR. Iowa/e0 P.70WEA L, M

ATTORNEYS,

Patented 'Sept. 26, 1933 SHINGLE-LIKE SLAB FORMING PROCESS I AND APPARATUS Edward R. Powell, Alexandria, Ind.

Application November 28, 1930 Serial No. 498,619

12 Claims.

This invention relates to a permanent, strong, light weight material, particularly adaptable for use as shingles, structural sheets and the like.

, The chief object of this invention is to produce from local materials ceramic objects, such as those particularly adapted for use as shingles and the like.

The chief feature of the invention consists in the formation of .a ceramic object, such as adapted for shingle use, which is made from local clay and which will not deteriorate in use, bloom, eiiioresce or burn, and which will permit nails to be driven therethrough without cracking, and .which is light in weight, fireproof, and which will have some thermal insulating value and can be made in attractive, permanent colors and textures.

Such a ceramic material has an advantage over slate, Portland cement or asbestos shingles, in that it is economical to produce and furthermore, in that local clay maybe utilized as the basic ingredient.

The chief feature of the invention consists in the accomplishment of theforegoing object. The formation of-the material is dependent upon the high temperature quickly applied to the material, whereby the slab of said material is expansively burned.

The full nature of the invention will be understood from the accompanying drawing and the following description and claims.

In the drawing Fig. 1 is a central sectional view through apparatus suitable for forming a ceramic slab.

Fig. 2 is an elevational view of a pair of shaping rolls.

Fig. 3 is an enlarged sectional view through a portion of one form of a ceramic slab embodying the inventionand in its final form.

Fig. 4 is an enlarged sectional view of the green ware prior toflthe expansive burning.

Fig. 5 is a similarview of the expansively burned ware prior to the compression for smoothing the surface of the same.

Fig. 6 is a similar view' of the expansively burned ware following the smoothing operation.

Fig. 7 is an elevational View of a modified mechanism for forming a wire-inserted strip.

In'the drawing 10 indicates a support for a roll 11 of wire reinforcement. 12 indicates an idler roll, and 13 the strip of wire reinforcement which passes downwardly between a pair of spaced forming rolls 14. The clay material in suitable condition is supplied thereto on opposite 'sides of the wire reinforcement as at 15, or applied to one side and pressed through, as shown in Fig. 7.

The sheet of clay, or the like, with the wire reinforcement embodied therein, may if desired pass between a pair of compressing rolls 16 and thence between a pair of surface conditioning roll brushes 17., It is at this point that the material 18 for forming the glaze or conditioning the surface may be added to the clay sheet. The sheet or strip then passes downwardly through the upper opening or inlet 19 of a reverberatory furnace 20 and thence passes downwardly through the lower opening or outlet 21.

The clay strip after passing through outlet 21 and having been fired, may be passed between a pair of pressing rolls 22, which even up the surface or provide suitable surface conformations upon the sheet. These rolls (see Fig. 2) may be of a corrugated form for forming a longitudinally corrugated strip. These rolls require a slightly greater peripheral speed than the rolls 14 due to the elongation of heated strip: g

After passing through these rolls the sheet passes through cutting rolls or sizing rolls 23. The cut material may be received by a suitable conveybr, which may be of the endless type or which may be of the batch type, such as shown by the truck 24, the slabs thereon being indicated by thenumeral 25. The cut sheets are then annealed if desired. 7

Prior to annealing, however, there is applied to one face and at least one end a glaze or sealing surface, see Fig. 3. This is to protect the otherwise exposed ends of the reinforcement which eliminates rust and breaking in use.

The foregoing apparatus is suitable for performing the processes which produce the resulting article. The resulting article (see Fig. 3) includes a body portion of expansively burned clay 30, the expanded portions, in the form of isolated air pockets, or the like, being indicated by the numeral 31. The wire reinforcement is indicated by the numeral 32 and the article shown in Fig. 3 is provided with a glazed surface 33. This glaze may incorporate suitable coloring materials which are well known in the ceramic art. The slab may be formed from about A;" to approximately thick and the wire mesh may be anywhere from to 1" mesh and of about #28 to #16 size iron wire. This wire constitutes the reinforcement which gives the slab strength and resiliency.

As heretofore stated extremely rapid and an expansive type of burning of the clay body is necessary to protect the iron wire from being oxithe melting point of the iron or steel reinforcement. The rate of travel of the strip to the fur-.

nace is such that before the full temperature of the outer surface is communicated to the interior and to the wire, the strip is removed from the vicinity of the flame and rapidly cools so that the wire reinforcement neither melts nor oxidizes excessively. The wire is preferably of high carbon or alloy steel which has high tensile strength in annealed condition.

The glaze need not be added unless desired. The coloring need not be added unless desired. Both may be added if desired.

Since the expansive burning or expansion is uncontrolled the surface of the strip is and would be very irregular, so that the finishing rolls are required to smooth the surface to the desired texture and conformation and while the burnt clay is in suitable condition for operation thereon. After the slabs have been formed they may be annealed in the conventional manner. The unglazed slabs may, if desired, be subsequently glazed with a surface glazing material, in the conventional manner. The important feature, therefore, is that the travel of the sheet is so timed that the surface of the clay will have time to fuse by the time it is ready to be removed from the vicinity of the flame and the amount of heat that travels inwardly from the surface is just sufficient to secure the desired expansion in the body of the slab. The clay utilized is first won, crushed and tempered according to the standard practice employed for the particular clay utilized. Some clays will require the addition of a flux to lower the melting point for the present process. Some clays deficient in carbonates or equivalent material will require the addition of such material so that the clay will give off gas when heated.

The clay mix is preferably fairly stiff and it is supplied on one or both sides of the wire reinforcement and preferably is shredded to fall in small flakes between the rolls. Although in the present disclosure of the apparatus but a single pair of space-forming rolls are illustrated in order to obtain the desired thickness in the sheet, it may be necessary to position a plurality of pairs of rolls, each of which is associated with the sheet and each of which applies an additional layer of clay to the sheet for building up the thickness thereof.

There is preferably added to the sheet prior to its introduction to the flame a superficial coating of flux material to make the'surface melt readily. Such amaterial may consist of a layer of more fusible clay or such a slip coat may include soda, borax or other flux and metallic oxides as pigments and the like may be incorporated therein. This slip coat or surface material may be sprayed or brushed on to the clay body or may be otherwise applied, or same may be in emulsion form, powder form, or in any other suitable form as found expedient.

Ordinarily the surfaceof the sheet must be hot but still wet when it encounters the intense furnace heat. A dry surface is apt to spall. If the furnace wall is thick, a shield 120 jacketed at 121 may be used to protect the surface from drying too soon. With certain clays, a rough texture on the clay body is advisable; also the use of acid, sodium silicate or other material which froths on the surface may prove beneficial.

Figs- 4, 5 and 6 illustrate the several stages of the product during the process.

In Fig. 4 the green ware is illustrated prior to the application of the glaze coat and like material. It represents the material just after it has passed between rolls 16.

Fig. 5 illustrates the ware after it has passed through the opening 21 and immediately prior to its introduction between rolls 22.

Fig. 6 illustrates the ware immediately following its passage between rolls 22.

The invention claimed is:

1. The process of making ceramic sheets including the formation of a reinforced sheet of clay, forming successive layers of said sheet which have varying water concentration, and burning same expansively.

2. The process of making a ceramic sheet including the formation of a reinforced sheet of clay, forming successive layers of said sheet which have varying fusibility, and burning same expansively.

3. The process of making ceramic sheets including the steps of forming continuously a reinforced strip of expansively burned material, severing same into units, and glazing to protect the exposed reinforcement.

4. The process of forming ceramic sheets including the formation of a relatively dense reinforced clay sheet, conditioning the surface thereof, and burning so as to obtain a sheet of increased thickness.

5. The process of making ceramic sheets including the steps of preparing relatively stiff plastic clay suitable for expansive burning, forming a relatively homogeneous body thereof around a metal reinforcement, and burning so as to obtain a cellular structure in the clay.

6. The process of making ceramic sheets including the steps of preparing a dense reinforced sheet of relatively stiff clay, adding surface conditioning material thereto, burning so as to obtain a cellular structure, and forming while in pyro-plastic condition.

'7. The process of making ceramic sheets including the formation of a continuous reinforced strip of dense clay, conditioning the surface thereof, burning so as to materially lessen the density, forming while in pyro-plastic condition, and severing into units.

8. The process of forming a ceramic slab and the like, including initially forming a strip of moist clay, subjecting the strip for a limited period to a relatively high temperature for expansively burning the strip irrespective of its burned form, and then reforming the strip to the desired outline.

9. An apparatus for forming a reinforced ceramic sheet, including in combination means for imbedding wire reinforcements in soft clay, means for conditioning the surface of the clay, and means for subjecting same suddenly to temperatures in excess of melting point of reinforcing and suflicient to cause expansive burning of said clay.

10. An apparatus for forming a reinforced ceramic sheet, including in combination means for feeding a strip of metal reinforcement, means for supplying a sheet of expansively burned clay in enclosing relation relative to the reinforcement, and means operating at aperipheral speed greater than the speed of the strip for forming units therefrom.

11. An apparatus for forming a reinforced ceramic sheet, including in combination means for forming a continuous strip of metal reinforced clay capable of expansive burning and with the aeaaasa i a1 time water-mixed clay said means operating at a predetermined peripheral speed, means for conditioning the surface of the clay, means for heating the strip to cause incipient fusion of the surface and expansive burning of the clay mass, and other means operated at slightly greater peripheral speed than the molding means for receiving the strip.

EDWARD R. POWELL. 

